1. Field of the Invention
The present invention relates to a static balance-adjusted wheel for a vehicle, and the like; a method for manufacturing a static balance-adjusted wheel; and a method for adjusting the balance of the wheel.
2. Prior Art
With wheels (tire/wheel assemblies) for vehicles, and the like, balance in the circumferential direction of the rotation axis and in the direction of the rotation axis must be adjusted when the tire and wheel are assembled together.
The condition in which balance in the direction about the circumference of the rotation axis is not adjusted is called static unbalance, which causes vibration of the vehicle body in the vertical direction. The condition in which balance in the direction along the rotation axis is not adjusted is called dynamic unbalance, which causes vibration of the vehicle body in the vertical and lateral directions, as well as steering shimmy.
A method described below has been used conventionally for adjusting the balance of the tire/wheel assembly. With the conventional method, a wheel and a tire are assembled by aligning the direction of the radial force variation (RFV), which is strongest in the radial direction of a tire, with the direction of the low point, which is at the location of the smallest diameter in the peripheral direction of the wheel. When the lightest point along the periphery of a tire, does not align with the heaviest point therealong, balance weights must be attached to the wheel onto which a tire is assembled for balancing the tire/wheel assembly.
For determining a location at which the balance weight is attached, the direction and amount of the unbalance of tire/wheel assembly is measured by an unbalance-measuring instrument. Depending on the measurement result, a balance weight, which will match an unbalanced direction and an unbalanced amount of assembled tire/wheel assembly, is chosen, and attached to the periphery of the wheel side face. Then, the balance of a tire/wheel assembly is adjusted by repeating the positioning of the balance weight and measurement of the unbalanced amount of a tire/wheel assembly until the unbalanced amount of the tire/wheel assembly becomes lower than a predetermined value.
For this balance adjusting operation, many processes and complicated works are needed, so that a great number of processes are thus required for this balance adjusting operation. Furthermore, when a balance weight is attached to the outer surface of the wheel, the appearance of the wheel will be spoiled. Therefore, it is desirable that the size of the balance weight is as small as possible, and it is more desirable that the balance of the tire/wheel assembly is adjusted without attaching a balance weight. It is further desirable that the location at which a balance weight is attached can be determined without measuring balance even if the balance weight must be attached.
With the wheel, since the heaviest point of the wheel tends to accord with the location of the air valve, when a tire is assembled onto the wheel, the location where the balance weight is attached may be determined using the location of the air valve as a marker. With conventional wheels, however, the heaviest point does not necessarily accord with the location of an air valve. The location of the air valve thus cannot always be used as a marker showing the heaviest point.
It is therefore an object of the present invention to provide a balance adjustable wheel, and to improve the appearance of such wheel or to improve the assembly efficiency of such wheel and a tire.
In order to overcome above described problems, the peak of thickness, which exists near the center of the width direction of a rolled plate, is identified. Then, by means of the invention, the balance of the wheel can be controlled with ease by combining the deviation of the balance of a disk having a variable thickness with the deviation of the balance caused by the weight of the air valve.
According to the present invention, which attains these and other objects, there is provided a wheel having a disk which is formed by dividing a rolled plate into a plurality of circumferential sections, the wheel being characterized in that an air valve insertion hole is provided at a predetermined angle position on the basis of the location of a thick part of the disk from the center of the disk.
With this invention, when the unbalance caused by the thick part and the. unbalance caused by the air valve are expressed by a vector from the center of the disk, respectively, the heaviest point of the wheel will be located at the position at which these vectors are compounded. Balance of the wheel thus can be adjusted at a desired location by setting the air valve insertion hole, into which the air valve is attached, at the suitable location.
Since the wheel in which unbalance has been produced in the desired direction may be obtained, plural wheels in which unbalancing locations occur can be manufactured. Therefore, when the tire is to be assembled with the wheel, the wheel is selected which has the same angle between the low point location and the heaviest location from the center of wheel as the angle between the RFV location and the lightest point location determined from the center of the tire upon assembly, whereby, unbalance of the tire/wheel assembly is offset by the heaviest point and lightest point. The balance of the tire/wheel assembly can thus be adjusted with minimum effort.
According to another aspect of the present invention, there is provided a wheel having a disk which is formed by dividing a rolled plate into plural circumferential sections, the wheel is characterized in that the location of a thick part of the disk from the center of the disk and the location containing an air valve insertion hole are overlapped.
With this other aspect of the present invention, since the location of the thick part, which tends to become the heaviest point, as viewed from the center of the wheel, and the location of the air valve are overlapped, the location in which the air valve is provided certainly serves as the heaviest point. The assembling operation of the tire/wheel assembly thus can be adjusted with ease by using the location of the air valve as a marker showing the heaviest point.
According to the manufacturing method of the present invention, there is provided a method for manufacturing a wheel in which a rolled plate of varying transverse thickness is used, the method comprising the steps of: forming a disk from a divided part which is obtained by dividing the rolled plate; and engaging the disk to a rim in the condition that an air valve insertion hole on the rim is provided at a position shifted for a predetermined angle from the location of a thick part of the disk measured from the center of the disk.
With the present assembling method, when the unbalance caused by the thick part of the disk and the unbalance caused by the air valve are each expressed by a vector which is extended from the center of the disk, respectively, the wheel in which the heaviest point thereof is positioned in the direction of the vector obtained by combining both vectors can be manufactured. Therefore, a wheel having the desired balance can be manufactured by determining the predetermined angle required for the location of the air valve insertion hole with respect to the thick part of the disk as measured from the center of the disk.
According to another manufacturing method of the present invention, there is provided a method for manufacturing the wheel in which rolled plates of varying transverse thickness are used, the method comprising the step of: forming a disk from a divided part which is obtained by dividing the rolled plate; and attaching the disk to a rim in the condition that the location of a thick part of the disk measured from the center of the disk and the location of an air valve insertion hole are overlapped.
With another assembling method, the air valve can be provided in the region of the thick part, which is the heavy region of the disk, whereby the wheel with the assembled air valve certainly serving as the heaviest point can be manufactured.
According to the method for adjusting the balance of a wheel, there is provided a method for adjusting the balance of a wheel which is formed by fixing a rim to a disk obtained by dividing a rolled plate of varying transverse thickness into a plurality of disks along the rolling direction, the method is characterized in that the rim is fixed to a disk in the condition that an air valve insertion hole on the rim is provided at a position shifted by a predetermined angle from the location of a thick part of the disk measured from the center of the disk.
With the present balance of wheel adjusting method, since the air valve can be provided at the location which is shifted by the amount of a predetermined angle with respect to the thick part location measured from the center of a disk, the heaviest point of the wheel will be positioned in at the location of a vector obtained by combining the vectors extending from the center of the disk representing the unbalance caused by the thick part of the disk and the unbalance caused by the air valve, respectively.
Here, joining may be performed by any method by which the rim and the disk can be joined without damaging the function of the wheel, and various known methods, for example, welding, brazing, bolting, adhesion by adhesive agent, etc., may be used.